An interim nuclear deal between Iran and six world powers will start on January 20th.
Under the terms of the agreement, which was reached in November, Iran will see some sanctions suspended as soon as the deal takes effect.
Tehran has agreed to halt enrichment of uranium above five-percent purity, and "neutralize" its stockpile of near-20-percent-enriched uranium.
The deal gives world powers and Tehran six months to agree on a complete end to a standoff that has raised the risk of a wider Middle East war.
U.S. President Barack Obama welcomed the news but U.S. Secretary of State John Kerry cautioned that the next stage in negotiations would be "very difficult."
The EU's foreign policy chief Catherine Ashton said the world powers will ask the International Atomic Energy Agency to verify the deal's implementation.

Why are we pushing for war when a path to peace has been laid out?
Though the Iranians are easy to dislike -- having done us wrong in the hostage crisis of 1979 -- we need to move past that. Perpetuating old hostilities is not the way to move forward.
The President's reasoning seems right: “Unprecedented sanctions and tough diplomacy helped to bring Iran to the negotiating table. Imposing additional sanctions now will only risk derailing our efforts.”
The new sanctions, therefore, should not survive a veto.
If the President is wrong, our framework is still in place to clobber Iran.
But why would Iran want to prove him wrong? November's agreement is the only path to normalcy for that country.